The present invention relates to novel hepatitis C virus (xe2x80x9cHCVxe2x80x9d) protease inhibitors, pharmaceutical compositions containing one or more such inhibitors, methods of preparing such inhibitors and methods of using such inhibitors to treat hepatitis C and related disorders. This invention specifically discloses novel peptide compounds as inhibitors of the HCV NS3/NS4a serine protease.
Hepatitis C virus (HCV) is a (+)-sense single-stranded RNA virus that has been implicated as the major causative agent in non-A, non-B hepatitis (NANBH), particularly in blood-associated NANBH (BB-NANBH)(see, International Patent Application Publication No. WO 89/04669 and European Patent Application Publication No. EP 381 216). NANBH is to be distinguished from other types of viral-induced liver disease, such as hepatitis A virus (HAV), hepatitis B virus (HBV), delta hepatitis virus (HDV), cytomegalovirus (CMV) and Epstein-Barr virus (EBV), as well as from other forms of liver disease such as alcoholism and primary biliar cirrhosis.
Recently, an HCV protease necessary for polypeptide processing and viral replication has been identified, cloned and expressed; (see, e.g., U.S. Pat. No. 5,712,145). This approximately 3000 amino acid polyprotein contains, from the amino terminus to the carboxy terminus, a nucleocapsid protein (C), envelope proteins (E1 and E2) and several non-structural proteins (NS1, 2, 3, 4a, 5a and 5b). NS3 is an approximately 68 kda protein, encoded by approximately 1893 nucleotides of the HCV genome, and has two distinct domains: (a) a serine protease domain consisting of approximately 200 of the N-terminal amino acids; and (b) an RNA-dependent ATPase domain at the C-terminus of the protein. The NS3 protease is considered a member of the chymotrypsin family because of similarities in protein sequence, overall three-dimensional structure and mechanism of catalysis. Other chymotrypsin-like enzymes are elastase, factor Xa, thrombin, trypsin, plasmin, urokinase, tPA and PSA. The HCV NS3 serine protease is responsible for proteolysis of the polypeptide (polyprotein) at the NS3/NS4a, NS4a/NS4b, NS4b/NS5a and NS5a/NS5b junctions and is thus responsible for generating four viral proteins during viral replication. This has made the HCV NS3 serine protease an attractive target for antiviral chemotherapy.
It has been determined that the NS4a protein, an approximately 6 kda polypeptide, is a co-factor for the serine protease activity of NS3. Autocleavage of the NS3/NS4a junction by the NS3/NS4a serine protease occurs intramolecularly (i.e., cis) while the other cleavage sites are processed intermolecularly (i.e. trans).
Analysis of the natural cleavage sites for HCV protease revealed the presence of cysteine at P1 and serine at P1xe2x80x2 and that these residues are strictly conserved in the NS4a/NS4b, NS4b/NS5a and NS5a/NS5b junctions. The NS3/NS4a junction contains a threonine at P1 and a serine at P1xe2x80x2. The Cysxe2x86x92Thr substitution at NS3/NS4a is postulated to account for the requirement of cis rather than trans processing at this junction. See, e.g., Pizzi et al. (1994) Proc. Natl. Acad. Sci (USA) 91 :888-892, Failla et al. (1996) Folding and Design 1:35-42. The NS3/NS4a cleavage site is also more tolerant of mutagenesis than the other sites. See, e.g., Kollykhalov et al. (1994) J. Virol. 68:7525-7533. It has also been found that acidic residues in the region upstream of the cleavage site are required for efficient cleavage. See, e.g., Komoda et al. (1994) J. Virol. 68:7351-7357.
Inhibitors of HCV protease that have been reported include antioxidants (see, International Patent Application Publication No. WO 98/14181), certain peptides and peptide analogs (see, International Patent Application Publication No. WO 98/17679, Landro et al. (1997) Biochem. 36:9340-9348, Ingallinella et al. (1998) Biochem. 37:8906-8914, Llinàs-Brunet et al. (1998) Bioorg. Med. Chem. Lett. 8:1713-1718), inhibitors based on the 70-amino acid polypeptide eglin c (Martin et al. (1998) Biochem. 37:11459-11468, inhibitors affinity selected from human pancreatic secretory trypsin inhibitor (hPSTI-C3) and minibody repertoires (MBip) (Dimasi et al. (1997) J. Virol. 71:7461-7469), cVHE2 (a xe2x80x9ccamelizedxe2x80x9d variable domain antibody fragment) (Martin et al.(1997) Protein Eng. 10:607-614), and xcex11-antichymotrypsin (ACT) (Elzouki et al.) (1997) J. Hepat. 27:42-28). A ribozyme designed to selectively destroy hepatitis C virus RNA has recently been disclosed (see, BioWorld Today 9(217): 4 (Nov. 10, 1998)).
Reference is also made to the PCT Publications, No. WO 98/17679, published Apr. 30, 1998 (Vertex Pharmaceuticals Incorporated); WO 98/22496, published May 28, 1998 (F. Hoffmann-La Roche A G); and WO 99/07734, published Feb. 18, 1999 (Boehringer Ingelheim Canada Ltd.).
HCV has been implicated in cirrhosis of the liver and in induction of hepatocellular carcinoma. The prognosis for patients suffering from HCV infection is currently poor. HCV infection is more difficult to treat than other forms of hepatitis due to the lack of immunity or remission associated with HCV infection. Current data indicates a less than 50% survival rate at four years post cirrhosis diagnosis. Patients diagnosed with localized resectable hepatocellular carcinoma have a five-year survival rate of 10-30%, whereas those with localized unresectable hepatocellular carcinoma have a five-year survival rate of less than 1%.
Reference is made to A. Marchetti et al, Synlett, S1, 1000-1002 (1999) describing the synthesis of bicylic analogs of an inhibitor of HCV NS3 protease. A compound disclosed therein has the formula: 
Reference is also made to WO 00/09558 (Assignee: Boehringer Ingelheim Limited; Published Feb. 24, 2000) which discloses peptide derivatives of the formula: 
where the various elements are defined therein. An illustrative compound of that series is: 
Reference is also made to WO 00/09543 (Assignee: Boehringer Ingelheim Limited; Published Feb. 24, 2000) which discloses peptide derivatives of the formula: 
where the various elements are defined therein. An illustrative compound of that series is: 
Current therapies for hepatitis C include interferon-xcex1 (INFxcex1) and combination therapy with ribavirin and interferon. See, e.g., Beremguer et al. (1998) Proc. Assoc. Am. Physicians 110(2):98-112. These therapies suffer from a low sustained response rate and frequent side effects. See, e.g. Hoofnagle et al. (1997) N. Engl. J. Med. 336:347. Currently, no vaccine is available for HCV infection.
Pending and copending U.S. patent application Serial No. 60/220,110, filed Jul. 21, 2000, Serial No. 60/220,107, filed Jul. 21, 2000, Serial No. 60/220,108, filed Jul. 21, 2000, Serial No. 60/220,101, filed Jul. 21, 2000, Serial No. 60/254,869, filed Dec. 12, 2000, Serial No. 60/194,607, filed Apr. 5, 2000, and Serial No. 60/198,204, filed Apr. 19, 2000 disclose various types of peptides as NS-3 serine protease inhibitors of hepatitis C virus.
There is a need for new treatments and therapies for HCV infection. It is, therefore, an object of this invention to provide compounds useful in the treatment or prevention or amelioration of one or more symptoms of hepatitis C.
It is a further object herein to provide methods of treatment or prevention or amelioration of one or more symptoms of hepatitis C.
A still further object of the present invention is to provide methods for modulating the activity of serine proteases, particularly the HCV NS3/NS4a serine protease, using the compounds provided herein.
Another object herein is to provide methods of modulating the processing of the HCV polypeptide using the compounds provided herein.
In its many embodiments, the present invention provides a novel class of inhibitors of the HCV protease, pharmaceutical compositions containing one or more of the compounds, methods of preparing pharmaceutical formulations comprising one or more such compounds, and methods of treatment, prevention or amelioration or one or more of the symptoms of hepatitis C. Also provided are methods of modulating the interaction of an HCV polypeptide with HCV protease. Among the compounds provided herein, compounds that inhibit HCV NS3/NS4a serine protease activity are preferred. The presently disclosed compounds generally contain about four or more amino acid residues and less than about twelve amino acid residues. Specifically, the present application discloses peptide compounds, defined further below.
In its first embodiment, the present invention provides a compound of Formula I: 
or a pharmaceutically acceptable salt, solvate or derivative thereof, wherein:
Z is O, NH or NR12;
X is alkylsulfonyl, heterocyclylsulfonyl, heterocyclylalkylsulfonyl, arylsulfonyl, heteroarylsulfonyl, alkylcarbonyl, heterocyclylcarbonyl, heterocyclylalkylcarbonyl, arylcarbonyl, heteroarylcarbonyl, alkoxycarbonyl, heterocyclyloxycarbonyl, aryloxycarbonyl, heteroaryloxycarbonyl, alkyaminocarbonyl, heterocyclylaminocarbonyl, arylaminocarbonyl, or heteroarylaminocarbonyl moiety, with the proviso that X may be additionally optionally substituted with R12 or R13;
X1 is H; C1-C4 straight chain alkyl; C1-C4 branched alkyl or; CH2-aryl (substituted or unsubstituted);
R12 is alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkyl-alkyl, heterocyclyl, heterocyclylalkyl, aryl, alkylaryl, arylalkyl, heteroaryl, alkylheteroaryl, or heteroarylalkyl moiety, with the proviso that R12 may be additionally optionally substituted with R13.
R13 is hydroxy, alkoxy, aryloxy, thio, alkylthio, arylthio, amino, alkylamino, arylamino, alkylsulfonyl, arylsulfonyl, alkylsulfonamido, arylsulfonamido, carboxy, carbalkoxy, carboxamido, alkoxycarbonylamino, alkoxycarbonyloxy, alkylureido, arylureido, halogen, cyano, or nitro moiety, with the proviso that the alkyl, alkoxy, and aryl may be additionally optionally substituted with moieties independently selected from R13.
P1a, P1b, P2, P3, P4, P5, and P6 are independently:
H; C1-C10 straight or branched chain alkyl; C2-C10 straight or branched chain alkenyl;
C3-C8 cycloalkyl, C3-C8 heterocyclic; (cycloalkyl)alkyl or (heterocyclyl)alkyl, wherein said cycloalkyl is made up of 3 to 8 carbon atoms, and zero to 6 oxygen, nitrogen, sulfur, or phosphorus atoms, and said alkyl is of 1 to 6 carbon atoms;
aryl, heteroaryl, arylalkyl, or heteroarylalkyl, wherein said alkyl is of 1 to 6 carbon atoms;
wherein all aforesaid alkyl, alkenyl, cycloalkyl, heterocyclyl; (cycloalkyl)alkyl and (heterocyclyl)alkyl moieties may be optionally substituted with R13. Additionally, the atoms of P1a and P1b may be joined to each other in such a fashion to form a spirocyclic or spiroheterocyclic ring, with said spirocyclic or spiroheterocyclic ring containing zero to 6 oxygen, nitrogen, sulfur, or phosphorus atoms, and may be optionally substituted with R13.
P1xe2x80x2 is H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkyl-alkyl, heterocyclyl, heterocyclyl-alkyl, aryl, aryl-alkyl, heteroaryl, or heteroaryl-alkyl; with the proviso that said P1xe2x80x2 may be additionally optionally substituted with R13.
Among the above-stated definitions for X, R12, R13, P1a, P1b, P2, P3, P4, P5, and P1xe2x80x2, the preferred groups for the various moieties are as follows:
Preferred moieties for X are: 
wherein Alkyl is C1 to C4 straight or branched chain, and wherein Aryl is phenyl or substituted phenyl.
Preferred moieties for P6 are: 
with n being 1-4.
Preferred moieties for P5 are: 
with n being 1-4; additionally, P6 and P5 may be the same or different.
Preferred moieties for R1 are OH, O-t-Bu, OR3, NHR3, NH-phenyl or NH-trityl.
Preferred moieties for R3 are H, C1 to C4 straight or branched chain alkyl
P3 and P4 may be the same or different and preferred moieties for P3 and P4 are: 
Preferred moieties for P2 are: 
wherein n=0, 1, 2 or 3;
Preferred moieties for P1a and P1b are: 
Preferred moieties for P1xe2x80x2 are: 
In another embodiment, the present invention provides a compound of Formula II: 
wherein X, P6, P5, P4, P3, P2, P1a, P1b and P1xe2x80x2 are as defined above. Z is O, NH or NR12 where R12 has been defined before. In Formula II, P2, when connected with the N atom adjacent to C atom it is attached to, forms a cyclic ring, with the proviso that said cyclic ring does not contain a carbonyl group as part of the cyclic ring structure. The cyclic ring moiety comprised of P2, the carbon atom to which P2 is attached, and the nitrogen atom adjacent to that carbon atom is noted above as: 
which may denote a five-membered ring or a six-membered ring structure. Preferred representatives for that cyclic ring structure are selected from the following: 
wherein:
R2 and R3 may be the same or different and are selected from H; C1-C6 straight chain alkyl; C1-C6 branched alkyl or cycloalkyl;
R4 is CO-Alkyl (alkyl being C1-C6 straight chain or branched or cycloalkyl); CO-aryl; COO-alkyl or COO-aryl;
R5 and R6 may be the same or different and are selected from H; C1-C3 straight chain alkyl; or C1-C3 branched alkyl;
R7 and R8 may be the same or different and are selected from H; C1-C3 straight chain alkyl; C1-C3 branched alkyl or CH2OH;
R9 and R10 may be the same or different and are selected from H; C1-C3 straight chain alkyl; C1-C3 branched alkyl; COOMe; COOH or CH2OH;
R11 is C1-C6 straight chain alkyl; C1-C6 branched alkyl; cyclocalkyl; or CH2-aryl (substituted or unsubstituted);
Z1 and Z2 may be the same or different and are selected from S; O; or CH2;
Z3 is CH2; S, SO2; NH or NR4; 
Z4 and Z5 may be the same or different and are selected from S, O or CH2.
In yet another embodiment, the present invention discloses compounds of Formula III: 
where the various elements are as defined above.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this invention belongs. Thus, for example, the term alkyl (including the alkyl portions of alkoxy) refers to a monovalent group derived from a straight or branched chain saturated hydrocarbon by the removal of a single atom having from 1 to 8 carbon atoms, preferably from 1 to 6;
arylxe2x80x94represents a carbocyclic group having from 6 to 14 carbon atoms and having at least one benzenoid ring, with all available substitutable aromatic carbon atoms of the carbocyclic group being intended as possible points of attachment. Preferred aryl groups include phenyl, 1-naphthyl, 2-naphthyl and indanyl, and especially phenyl and substituted phenyl;
aralkylxe2x80x94represents a moiety containing an aryl group linked vial a lower alkyl;
alkylarylxe2x80x94represents a moiety containing a lower alkyl linked via an aryl group;
cycloalkylxe2x80x94represents a saturated carbocyclic ring having from 3 to 8 carbon atoms, preferably 5 or 6, optionally substituted.
heterocyclicxe2x80x94represents, in addition to the heteroaryl groups defined below, saturated and unsaturated cyclic organic groups having at least one O, S and/or N atom interrupting a carbocyclic ring structure that consists of one ring or two fused rings, wherein each ring is 5-, 6- or 7-membered and may or may not have double bonds that lack delocalized pi electrons, which ring structure has from 2 to 8, preferably from 3 to 6 carbon atoms, e.g., 2- or 3-piperidinyl, 2- or 3-piperazinyl, 2- or 3-morpholinyl, or 2- or 3-thiomorpholinyl;
halogenxe2x80x94represents fluorine, chlorine, bromine and iodine;
heteroarylxe2x80x94represents a cyclic organic group having at least one O, S and/or N atom interrupting a carbocyclic ring structure and having a sufficient number of delocalized pi electrons to provide aromatic character, with the aromatic heterocyclyl group having from 2 to 14, preferably 4 or 5 carbon atoms, e.g., 2-, 3- or 4-pyridyl, 2- or 3-furyl, 2- or 3-thienyl, 2-, 4- or 5-thiazolyl, 2- or 4-imidazolyl, 2-, 4- or 5-pyrimidinyl, 2-pyrazinyl, or 3- or 4-pyridazinyl, etc. Preferred heteroaryl groups are 2-, 3- and 4-pyridyl; such heteroaryl groups may also be optionally substituted.
Also included in the invention are tautomers, rotamers, enantiomers and other optical isomers of compounds of Formula I, Formula II and Formula III, as well as pharmaceutically acceptable salts, solvates and derivatives thereof.
A further feature of the invention is pharmaceutical compositions containing as active ingredient a compound of Formula I, Formula II or Formula III (or its salt, solvate or isomers) together with a pharmaceutically acceptable carrier or excipient.
The invention also provides methods for preparing compounds of Formulas I, II and III, as well as methods for treating diseases such as, for example, HCV and related disorders. The methods for treating comprise administering to a patient suffering from said disease or diseases a therapeutically effective amount of a compound of Formula I, II or III, or pharmaceutical compositions comprising a compound of Formula I, II or III.
Also disclosed is the use of a compound of Formulas I, II or III for the manufacture of a medicament for treating HCV and related disorders.
In one embodiment, the present invention discloses compounds of Formula I as inhibitors of HCV protease, especially the HCV NS3/NS4a serine protease, or a pharmaceutically acceptable derivative thereof, where the various definitions are given above.
In another embodiment, the present invention discloses compounds of Formula II as inhibitors of HCV protease, especially the HCV NS3/NS4a serine protease, or a pharmaceutically acceptable derivative thereof, where the various definitions are given above.
In another embodiment, the present invention discloses compounds of Formula III as inhibitors of HCV protease, especially the HCV NS3/NS4a serine protease, or a pharmaceutically acceptable derivative thereof, where the various definitions are given above.
Representative compounds of the invention which exhibit excellent HCV protease inhibitory activity are listed below in Table 1 along with their activity (ranges of Ki* values in nanomolar, nM).
Category a=1-100 nM; Category b=101-999 nM; Category c=1000-10,000.
Some of the types of the inventive compounds and methods of synthesizing the various types of the inventive compounds of both Formula I and Formula II are listed below, then schematically described, followed by the illustrative Examples. 
Depending upon their structure, the compounds of the invention may form pharmaceutically acceptable salts with organic or inorganic acids, or organic or inorganic bases. Examples of suitable acids for such salt formation are hydrochloric, sulfuric, phosphoric, acetic, citric, malonic, salicylic, malic, fumaric, succinic, ascorbic, maleic, methanesulfonic and other mineral and carboxylic acids well known to those skilled in the art. For formation of salts with bases, suitable bases are, for example, NaOH, KOH, NH4OH, tetraalkylammonium hydroxide, and the like.
In another embodiment, this invention provides pharmaceutical compositions comprising the inventive peptides as an active ingredient. The pharmaceutical compositions generally additionally comprise a pharmaceutically acceptable carrier diluent, excipient or carrier (collectively referred to herein as carrier materials). Because of their HCV inhibitory activity, such pharmaceutical compositions possess utility in treating hepatitis C and related disorders.
In yet another embodiment, the present invention discloses methods for preparing pharmaceutical compositions comprising the inventive compounds as an active ingredient. In the pharmaceutical compositions and methods of the present invention, the active ingredients will typically be administered in admixture with suitable carrier materials suitably selected with respect to the intended form of administration, i.e. oral tablets, capsules (either solid-filled, semi-solid filled or liquid filled), powders for constitution, oral gels, elixirs, dispersible granules, syrups, suspensions, and the like, and consistent with conventional pharmaceutical practices. For example, for oral administration in the form of tablets or capsules, the active drug component may be combined with any oral non-toxic pharmaceutically acceptable inert carrier, such as lactose, starch, sucrose, cellulose, magnesium stearate, dicalcium phosphate, calcium sulfate, talc, mannitol, ethyl alcohol (liquid forms) and the like. Moreover, when desired or needed, suitable binders, lubricants, disintegrating agents and coloring agents may also be incorporated in the mixture. Powders and tablets may be comprised of from about 5 to about 95 percent inventive composition. Suitable binders include starch, gelatin, natural sugars, corn sweeteners, natural and synthetic gums such as acacia, sodium alginate, carboxymethylcellulose, polyethylene glycol and waxes. Among the lubricants there may be mentioned for use in these dosage forms, boric acid, sodium benzoate, sodium acetate, sodium chloride, and the like. Disintegrants include starch, methylcellulose, guar gum and the like.
Sweetening and flavoring agents and preservatives may also be included where appropriate. Some of the terms noted above, namely disintegrants, diluents, lubricants, binders and the like, are discussed in more detail below.
Additionally, the compositions of the present invention may be formulated in sustained release form to provide the rate controlled release of any one or more of the components or active ingredients to optimize the therapeutic effects, i.e. HCV inhibitory activity and the like. Suitable dosage forms for sustained release include layered tablets containing layers of varying disintegration rates or controlled release polymeric matrices impregnated with the active components and shaped in tablet form or capsules containing such impregnated or encapsulated porous polymeric matrices.
Liquid form preparations include solutions, suspensions and emulsions. As an example may be mentioned water or water-propylene glycol solutions for parenteral injections or addition of sweeteners and pacifiers for oral solutions, suspensions and emulsions. Liquid form preparations may also include solutions for intranasal administration.
Aerosol preparations suitable for inhalation may include solutions and solids in powder form, which may be in combination with a pharmaceutically acceptable carrier such as inert compressed gas, e.g. nitrogen.
For preparing suppositories, a low melting wax such as a mixture of fatty acid glycerides such as cocoa butter is first melted, and the active ingredient is dispersed homogeneously therein by stirring or similar mixing. The molten homogeneous mixture is then poured into convenient sized molds, allowed to cool and thereby solidify.
Also included are solid form preparations which are intended to be converted, shortly before use, to liquid form preparations for either oral or parenteral administration. Such liquid forms include solutions, suspensions and emulsions.
The compounds of the invention may also be deliverable transdermally. The transdermal compositions may take the form of creams, lotions, aerosols and/or emulsions and can be included in a transdermal patch of the matrix or reservoir type as are conventional in the art for this purpose.
Preferably the compound is administered orally, intravenously or subcutaneously.
Preferably, the pharmaceutical preparation is in a unit dosage form. In such form, the preparation is subdivided into suitably sized unit doses containing appropriate quantities of the active components, e.g., an effective amount to achieve the desired purpose.
The quantity of the inventive active composition in a unit dose of preparation may be generally varied or adjusted from about 1.0 milligram to about 1,000 milligrams, preferably from about 1.0 to about 950 milligrams, more preferably from about 1.0 to about 500 milligrams, and typically from about 1 to about 250 milligrams, according to the particular application. The actual dosage employed may be varied depending upon the patient""s age, sex, weight and severity of the condition being treated. Such techniques are well known to those skilled in the art.
Generally, the human oral dosage form containing the active ingredients can be administered 1 or 2 times per day. The amount and frequency of the administration will be regulated according to the judgment of the attending clinician. A generally recommended daily dosage regimen for oral administration may range from about 1.0 milligram to about 1,000 milligrams per day, in single or divided doses.
Some useful terms are described below:
Capsulexe2x80x94refers to a special container or enclosure made of methyl cellulose, polyvinyl alcohols, or denatured gelatins or starch for holding or containing compositions comprising the active ingredients. Hard shell capsules are typically made of blends of relatively high gel strength bone and pork skin gelatins. The capsule itself may contain small amounts of dyes, opaquing agents, plasticizers and preservatives.
Tabletxe2x80x94refers to a compressed or molded solid dosage form containing the active ingredients with suitable diluents. The tablet can be prepared by compression of mixtures or granulations obtained by wet granulation, dry granulation or by compaction.
Oral gelxe2x80x94refers to the active ingredients dispersed or solubilized in a hydrophillic semi-solid matrix.
Powder for constitution refers to powder blends containing the active ingredients and suitable diluents which can be suspended in water or juices.
Diluentxe2x80x94refers to substances that usually make up the major portion of the composition or dosage form. Suitable diluents include sugars such as lactose, sucrose, mannitol and sorbitol; starches derived from wheat, corn, rice and potato; and celluloses such as microcrystalline cellulose. The amount of diluent in the composition can range from about 10 to about 90% by weight of the total composition, preferably from about 25 to about 75%, more preferably from about 30 to about 60% by weight, even more preferably from about 12 to about 60%.
Disintegrantxe2x80x94refers to materials added to the composition to help it break apart (disintegrate) and release the medicaments. Suitable disintegrants include starches; xe2x80x9ccold water solublexe2x80x9d modified starches such as sodium carboxymethyl starch; natural and synthetic gums such as locust bean, karaya, guar, tragacanth and agar; cellulose derivatives such as methylcellulose and sodium carboxymethylcellulose; microcrystalline celluloses and cross-linked microcrystalline celluloses such as sodium croscarmellose; alginates such as alginic acid and sodium alginate; clays such as bentonites; and effervescent mixtures. The amount of disintegrant in the composition can range from about 2 to about 15% by weight of the composition, more preferably from about 4 to about 10% by weight.
Binderxe2x80x94refers to substances that bind or xe2x80x9cgluexe2x80x9d powders together and make them cohesive by forming granules, thus serving as the xe2x80x9cadhesivexe2x80x9d in the formulation. Binders add cohesive strength already available in the diluent or bulking agent. Suitable binders include sugars such as sucrose; starches derived from wheat, corn rice and potato; natural gums such as acacia, gelatin and tragacanth; derivatives of seaweed such as alginic acid, sodium alginate and ammonium calcium alginate; cellulosic materials such as methylcellulose and sodium carboxymethylcellulose and hydroxypropylmethylcellulose; polyvinylpyrrolidone; and inorganics such as magnesium aluminum silicate. The amount of binder in the composition can range from about 2 to about 20% by weight of the composition, more preferably from about 3 to about 10% by weight, even more preferably from about 3 to about 6% by weight.
Lubricantxe2x80x94refers to a substance added to the dosage form to enable the tablet, granules, etc. after it has been compressed, to release from the mold or die by reducing friction or wear. Suitable lubricants include metallic stearates such as magnesium stearate, calcium stearate or potassium stearate; stearic acid; high melting point waxes; and water soluble lubricants such as sodium chloride, sodium benzoate, sodium acetate, sodium oleate, polyethylene glycols and dxe2x80x2l-leucine. Lubricants are usually added at the very last step before compression, since they must be present on the surfaces of the granules and in between them and the parts of the tablet press. The amount of lubricant in the composition can range from about 0.2 to about 5% by weight of the composition, preferably from about 0.5 to about 2%, more preferably from about 0.3 to about 1.5% by weight.
Glidentxe2x80x94material that prevents caking and improve the flow characteristics of granulations, so that flow is smooth and uniform. Suitable glidents include silicon dioxide and talc. The amount of glident in the composition can range from about 0.1% to about 5% by weight of the total composition, preferably from about 0.5 to about 2% by weight.
Coloring agentsxe2x80x94excipients that provide coloration to the composition or the dosage form. Such excipients can include food grade dyes and food grade dyes adsorbed onto a suitable adsorbent such as clay or aluminum oxide. The amount of the coloring agent can vary from about 0.1 to about 5% by weight of the composition, preferably from about 0.1 to about 1%.
Bioavailabilityxe2x80x94refers to the rate and extent to which the active drug ingredient or therapeutic moiety is absorbed into the systemic circulation from an administered dosage form as compared to a standard or control.
Conventional methods for preparing tablets are known. Such methods include dry methods such as direct compression and compression of granulation produced by compaction, or wet methods or other special procedures. Conventional methods for making other forms for administration such as, for example, capsules, suppositories and the like are also well known.
Another embodiment of the invention discloses the use of the pharmaceutical compositions disclosed above for treatment of diseases such as, for example, hepatitis C and the like. The method comprises administering a therapeutically effective amount of the inventive pharmaceutical composition to a patient having such a disease or diseases and in need of such a treatment.
In yet another embodiment, the compounds of the invention may be used for the treatment of HCV in humans in monotherapy mode or in a combination therapy mode such as, for example, in combination with antiviral agents such as, for example, ribavirin and/or interferon such as, for example, xcex1-interferon and the like.
As stated earlier, the invention includes tautomers, rotamers, enantiomers and other stereoisomers of the compounds also. Thus, as one skilled in the art appreciates, some of the inventive compounds may exist in suitable isomeric forms. Such variations are contemplated to be within the scope of the invention.
Another embodiment of the invention discloses a method of making the compounds disclosed herein. The compounds may be prepared by several techniques known in the art. Representative illustrative procedures are outlined in the following reaction schemes. It is to be understood that while the following illustrative schemes describe the preparation of a few representative inventive compounds, suitable substitution of any of both the natural and unnatural amino acids will result in the formation of the desired compounds based on such substitution. Such variations are contemplated to be within the scope of the invention.
Abbreviations which are used in the descriptions of the schemes, preparations and the examples that follow are:
THF: Tetrahydrofuran
DMF: N,N-Dimethylformamide
EtOAc: Ethyl acetate
AcOH: Acetic acid
HOOBt: 3-Hydroxy-1,2,3-benzotriazin-4(3H)-one
EDCl: 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride
NMM: N-Methylmorpholine
ADDP: 1,1xe2x80x2-(Azodicarbobyl)dipiperidine
DEAD: Diethylazodicarboxylate
DCC: Dicyclohexylcarbodiimide
HOBt: Hydroxybezotriazole
HATU: O-(7-Azabenzotriazol-1-yl)-N,N,Nxe2x80x2,Nxe2x80x2-tetramethyluronium hexafluorophosphate
TEMPO: 2,2,6,6-tetramethyl-1-piperidinyloxy free radical
TBTU: 2-(1H-Benzotriazole-1-yl)-1,1,3,3,-tetramethyluronium tetrafluoroborate
PAM: 4-Hydroxymethylphenylacetamidomethyl
DTT: Dithiothreitol
Hxc3xcnigs base (DIPEA or DIEA): Diisopropylethyl amine
DCM: Dichloromethane
MeOH: Methanol
EtOH: Ethanol
Et2O: Diethyl ether
PyBrOP: Bromo-tris-pyrrolidinophosphonium hexafluorophosphate
Trt: Trityl
PMB: Para-methoxybenzyl
Bzl=Bn: Benzyl
Boc: tert-Butyloxycarbonyl
Cbz: Benzyloxycarbonyl
Cp: Cylcopentyidienyl
Ts: p-toluenesulfonyl
Me: Methyl
General Preparative Schemes:
The following schemes describe the methods of synthesis of intermediate building blocks: 
Preparation of Intermediates:
The procedures to modify an amino acid with N-Boc, N-Cbz, COOBzl, COOBut, Obzl, Obut, COOMe, both putting them on or taking them off in the presence of each other in various combinations, are generally well known to those skilled in the art. Any modifications from the known procedures are noted herein.
Commercially Available Intermediates:
The following amino acids, used as P2 units in the preparation of the various inventive compounds, are commercially available, and were converted to their N-Boc derivatives with di-tert-butyidicarbonate, using known procedures. 
The following N-Boc-amino acids, used as P2 units, are commercially available. 
The following N-Boc-amino acid, used as P2 unit, is commercially available. After coupling the carboxylic acid, the Fmoc is removed by known treatment with piperidine before subsequent coupling. 
Certain intermediates which were not commercially available were synthesized, as needed, by following the procedures given below:
1. 
A. Mesylate:
A mixture of triphenylphosphine (8.7 g), toluene (200 mL), and methanesulfonic acid (2.07 mL) was stirred at 15xc2x0 C. while slowly adding diethylazidodicarboxylate (7.18 g) to maintain the temperature below 35xc2x0 C. The mixture was cooled to 20xc2x0 C., and the N-Boc amino acid (7.4 g, Bachem Biosciences, Inc.), and Et3N (1.45 mL) were added, and then the mixture was stirred at 70xc2x0 C. for 5 hr. The mixture was cooled to 5xc2x0 C., the organic supernate decanted, and solvent was removed from it in vacuo. The residue was stirred with Et2O (200 mL) until a precipitate deposits, the mixture was filtered, and the ethereal solution was chromatographed on silica gel (5:95 to 20:80 EtOAc-Et2O) to obtain the product (9.3 g), which was carried into the next step.
B. Azide
Sodium azide (1.98 g) was added to a solution of the product of the step above (9.3 g) in DMF (100 mL), and the mixture stirred at 70xc2x0 C. for 8 hr. The mixture was cooled, and poured into 5% aqueous NaHCO3, and extracted with EtOAc. The organic layer was washed with brine, then dried over anhydrous MgSO4. The mixture was filtered, and the filtrate evaporated in vacuo, to obtain the product (6.2 g), which was carried into the next step.
C. N-Cbz(4-N-Boc)-PrO-OMe
A solution of the product of the step above (0.6 g) in dioxane (40 mL) was treated with di-tert-butyidicarbonate (0.8 g), 10% Pd-C (0.03g), and hydrogen at one atmosphere for 18 hr. The mixture was filtered, the filtrate evaporated in vacuo, and the residue chromatographed on silica gel (1:1 to 2:1 Et2O-hexane) to obtain the product.
D. N-Cbz(4-N-Boc)-PrO-OH was prepared using known ester hydrolysis using LiOH.
2. Sulfones by Oxidation: 
These were prepared by following the procedure of U. Larsson, et al., Acta Chem. Scan., (1994), 48(6), 517-525. A solution of oxone(R) (20.2 g, from Aldrich Chemical Co.) in water (110 mL) was added slowly to a 0xc2x0 C. solution of the sulfide (7.2 g, from Bachem Biosciences, Inc.) in MeOH (100 mL). The cold bath was removed and the mixture stirred for 4 hr. The mixture was concentrated to xc2xd volume on a rotary evaporator, cold water (100 mL) added, extracted with EtOAc, the extract washed with brine, and then it was dried over anhydrous MgSO4. The mixture was filtered, and the filtrate evaporated in vacuo, to obtain the product as a white solid (7.7 g). A portion was crystallized from (i-Pr)2O to obtain an analytical sample, [xcex1]D+8.6 (c 0.8, CHCl3). Using the same procedure, the other sulfides shown were oxidized to sulfones to lead to the subject targets.